Electromagnetic fuel injectors are used in fuel injection systems for internal combustion engines to effectively control the discharge of fuel per unit time to the engine intake. Such electromagnetic fuel injectors are typically calibrated so as to inject a predetermined quantity of fuel per unit time prior to their installation in the fuel system.
Calibration of the fuel injector requires that both static and dynamic flow through the injector be precisely set and controlled. Typically, the static flow rate of such an injector is a function of the stroke of the valve assembly and is calibrated using a threaded spray tip. As the tip is rotated, the armature stroke, defined by the working air gap between the valve assembly and the solenoid pole piece, is increased or decreased. This method of adjustment is costly, and prone to thread damage and contamination which causes assembly difficulty. Additionally, as stroke is adjusted to accommodate static flow, the changing air gap length affects the magnetic circuit and therefore the dynamic flow rate of the injector.